#!/bin/bash
# 
# By using ec (Exif comment), a shell script with GUI, you can adjust the comments 
# of your EXIF data to your own needs. 
# ec allows you to edit the comments in a batch mode, 
# which comes in quite handy when you want a specific comment to go along with your photos.
#
# ec was written by bernd essl <bernd_at_b23.at>
# version 1.0

exiv2="/usr/bin/exiv2"
file="/usr/bin/file"
zenity="/usr/bin/zenity"

function setError() { 
    $zenity --error --text=$1
}

function getDependencies() {
    if [ ! -e $1 ]
    then
        package=`echo $1 | sed 's@/usr/bin/@@g'`
        echo "You have to install the package \"$package\" first!"
        exit 1
    fi
}


# check what we need
getDependencies $exiv2
getDependencies $file
getDependencies $zenity


# comment-dialog 
comment=$($zenity --entry --title="Text for the comment" --text="Text for the comment:")

if [ $? -eq 1 ]
then
    exit 1
fi


# picture-dialog
pictures=$($zenity --file-selection --multiple);

if [ $? -eq 1 ]
then 
    exit 1
fi


IFS='|'
for field in $pictures
do
    # writeable?
    if [ ! -w $field ] 
    then 
        setError "$field not writeable!"
        continue
    fi

    # JPEG?
    if [ ! `$file $field | /bin/grep "JPEG image data"` ]
    then
        setError "$field doesn't look like a JPEG!"
        continue
    fi

    echo "write comment: \"$comment\" in file: \"$field\""
    $exiv2 -M"set Exif.Photo.UserComment $comment" $field
done | $zenity --progress --pulsate --auto-close

$zenity --info --text="Done writing comments."